<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <!-- 引入外部js文件 -->
    <script src="js/jquery-1.8.3.js"></script>
</head>
<body>
    <div id="login">
        请登录！
    </div>
    <button>登录</button>
    <br>    
    <img src="images/eat.png" alt="" width="200" height="200" id="ganfan_id">
    <br>
    <button id="changeSize">修改大小</button>
    <div>123</div>444444
  
    <script>
        $(document).ready(function(){
            $("button").click(function(){
                $("#login").html("<b>欢迎您！<b>");

            });

            $("#changeSize").click(function(){
                $("#ganfan_id").attr("width","400px");
                $("#ganfan_id").attr({"width":"400px","height":"400px"});
            });

        });
    
        hide();
    </script>
</body>
</html>